The invention relates to a transistor switch with two control inputs, two transistors, and two supply voltage sources of different polarity which can be respectively connected to the transistors. The outputs of these transistors are in turn connected to the base control inputs of second switching transistors, the emitters of which are connected together to a common output and the collectors of which are connected across a voltage to be applied through these transistors to the output.
A transistor switch of this kind is known from the German AS No. 2,206,947, incorporated herein by reference. There, the transistors represent a two stage push-pull amplifier with complementary transistors, whereby the first transistor stage operates with a common load resistor via which the base contacts of the output side transistors are connected with one another.
From German OS No. 2,534,026, incorporated herein by reference, a device for the controlled switching of signals is known wherein a pulse control device releases rectangular-shaped control pulses to two control transformers. With the secondary side of these control transformers, in each case a first transistor is connected which functions as a switching transistor. To each of these first switching transistors a further transistor is connected such that one is connected with its collector to the positive terminal of a first supply voltage source and the other is connected with its emitter to the negative terminal of a second supply voltage source. The emitter, or respectively, collector of the two further transistors is connected to a first input of a synchronous motor, and a second input of the motor is connected to the negative pole of the first supply voltage source and to the positive pole of the second supply voltage source. The two transistor pairs form in each case a Darlington circuit whereby the connected transistors are reliably controlled in complete saturation. The collector-emitter path of the two further transistors are bridged in each case by a diode which protects the associated transistors against overload. This known circuit functions as a facsimile sender or a facsimile receiver containing a pivotably mounted drum which, by use of a synchronous motor, performs a scanning movement over different positions between a document placed around the drum and a converter.